The Bestina River rises near Serre di Rapolano and runs for about 7 kilometers, ending near the suburb of Camparboli in Asciano, where it joins with the Copra creek. The Bestina's continuous flow at variable levels and the considerable descent from its source to its mouth have allowed it to serve 11 mills for grain and metal processing. Along the course of the river are the remains of many hydraulic works: dams, channels and reservoirs, all designed for the best use of the hydraulic energy.
Upstream, the first molaring structure is that of Mulinuzzo. Presumably, its name derives from the discontinuous availability of water, not being able to reuse the one already passed by the previous mills. Below you will find the ruins of the Cornacchia mill, which still recognizes the water capture structures and the big gora, parallel to the watercourse.
Immediately under this windmill is the sloping barrier, designed to divert the water to the Tower of the Tower, the only fortified mill, perhaps located in defense of the upper part of the river, located far from the inhabited center. Along the way of pouring into the river of water used by the roof, there was another working mill thanks to the considerable altitude difference with that of the Tower.
Where the river receives the water of the above mills, there is a complex structure that, in addition to allowing the water to deviate from the palace, imposes on the river a path required by a large curved wall covering it to the existing waterfall behind the Field of the Fair. From here the river, lying in the Palace of Cacciaconti, arrives at the cascade of Commenda, where there is a water supply for the feeding of the great mountain serving the homonymous Mulino.
Under the cascade, which guarantees untouched water regimation, there is the invasion created directly along the riverbed and necessary to run the Mill of the Priests. The latter, along with the canals and locks built below, are the most important knot of the Valley of the Mulines. From here, it is possible to divert the water to the four subsequent Mills and all the internal water supplies to the historic center.
In fact, from below the waterfall on which the Mill of the Priests rests, the course of the river lowers so that they can no longer be exploited. The more downstream mills receive water sequentially, through canalization excavated in the gallezzone and predominantly underground, most of which still exist.